1. Technical Field
The present invention disclosure relates to a device to identify PC cards conforming to a standard , such as the PCMCIA (Personal Computer Memory Card International Association) standard, and a method of identifying such PC cards.
2. Discussion of the Background
Personal computers provided with a device to identify PC cards conforming to the PCMCIA standard (i.e., a so-called PC card slot) are known.
In a PC card conforming to the PCMCIA standard, a female-type connector is provided to a side surface of the card at the side of a short side of the card. The female-type connector is provided with first and second connect holes corresponding to pins of a plurality of pins of a male-type connector provided to a PC card control device, through which first and second card detect signals (defined as CD1# and CD2# by the PCMCIA standard and hereinafter referred to as CD1# and CD2#) flow, and third and fourth connect holes corresponding to pins of the plurality of pins of the male-type connector of the PC card control device, through which first and second voltage select signals (defined as VS1# and VS2# by the PCMCIA standard and hereinafter referred to as VS1# and VS2#) flow.
Inside of the PC card, wirings connected with the first and second connect holes are either grounded or connected with at least either of the third and fourth connect holes. In the PC card control device, both electrical potentials of CD1# and CD2# are in high-level states. When the PC card is connected with the PC card control device, the electrical potentials of CD1# and CD#2 change to low-level states. The PC card control device detects connection of the PC card with the PC card control device based on such a change in the electrical potentials of CD1# and CD2#.
Upon detecting connection of the PC card, the PC card control device detects respective states of CD2#, CD1#, VS2# and VS1# when an electrical potential of VS1# flowing through the third connect hole has been pulled up to a high-level state and when an electrical potential of VS2# flowing through the fourth connect hole has been pulled up to a high-level state, and identifies the type of the PC card (e.g., the signal level used by the PC card and the bit-width of the bus of the PC card) using the states of these signals CD2#, CD1#, VS2# and VS1# for identification information.
Japanese Patent Laid-open publication No. 2001-75746 describes a PC card control device, which recognizes a newly connected PC card. In the PC card control device, when electrical potential states of CD2#, CD1#, VS2#, and VS1# when electrical potentials of VS1# and VS2# flowing through the third and fourth connect holes are selectively pulled up to high-level states agree with an electrical potential state of a reserve PC card specified by the PCMCIA standard and signal states of specified pins other than the above-described pins of a male-type connector of the PC card control device satisfy predetermined conditions, an expansion card (smart card), a bus bit-width and a driving voltage of which have been specified in advance, is recognized.
The PC card control device described in the above JP Patent publication, however, checks signal states of specified pins of a male-type connector of the PC card control device in addition to acquiring regular identification information. Accordingly, a special identification algorithm for identifying expansion cards is necessary, thereby causing an increase in design steps of the PC card control device.